Software vendors are continually fixing, modifying, and enhancing the computer programs supplied to their customers. Typically, such changes are in response to bugs found in the programs, to the need for improved or more features, or a combination of both. In the past and still today, the predominant method of updating software and providing fixes is to supply customers a disc (e.g., floppy or CD-ROM) containing a complete new version of the program. Upon receipt of the upgrade disc, the customer installs the new version of the software on his or her computer. The installation process generally results in the old version of the program being overwritten with the new version.
There are several problems with this method of supplying upgrades. First, it generally takes a relatively large amount of time to produce sufficient quantities of discs for distribution to customers. Accordingly, such discs are released only once or twice a year. This reduces the speed at which customers can be supplied with fixes to their programs and may force them to operate the software with errors or other bugs for several months. Second, physical discs are expensive to create and deliver.
Thus, there have been some attempts to deliver upgrades via communication networks such as the Internet or by direct connection using modems. However, even with ever improving transmission capacity and reliability, transmission of large upgrade files can be difficult and time consuming to complete. In response to the difficulties of transmitting large complete files, patch technology has been developed that permits the transmission of smaller, partial programs. In many instances, only certain parts or files need to be repaired or updated in order to update a computer program. Therefore, only a partial or "patch" file needs to be transmitted to the end user. Generally, small files may be transmitted faster and more reliably than larger files. However, existing patch technology is unacceptable when anything more than minor changes need to be delivered to a customer. Accordingly, there is a need for an improved method and system of upgrading software using patches. More specifically, there is a need for an improved system and method of generating a patch file.